| Summary: | A research report submitted to the Faculty of Health Sciences,
University of the Witwatersrand, Johannesburg,
In partial fulfilment of the requirements for the degree of Master of Medicine in
Obstetrics and Gynaecology
February 2016 === Background and objectives
Menarche serves an important marker of female health for individuals and
populations. It indicates the onset of sexual maturation and reproductive
capacity, but also serves as a prognostic factor for future growth,
development, and the health of the individual and the population as a whole.
Birthweight and childhood growth are thought to affect the age at menarche
(AAM) through a number of different mechanisms but this relationship has yet
to be fully explored. The objectives of this study were:
1. To describe the age of onset of menarche in a population of healthy
‘normal weight’ females in the Birth to Twenty cohort.
2. To demonstrate the influence of birth weight on the age of menarche
3. To assess the impact of childhood growth on the age of menarche
4. To assess the contribution of weight gain during specific periods in
infancy and childhood on the age of menarche.
Design, setting and participants
Data from 788 South African children from the Birth to Twenty (Bt20)
prospective birth cohort study who were followed prospectively throughout
childhood were used. Variables included prenatal characteristics, birth
measurements, serial measurement of height and weight during childhood,
socio-economic status, and age at menarche. Exposures were weight at birth,
then at 2 years, and 4 years; and conditional weight gain (CWG) between
these ages. Outcome was age at menarche.
Results:
Age of onset of menarche: The average age of menarche in our sample was
12.66 years.
Relationship between birthweight on age of menarche: The findings of this
study show that birthweight does not significantly affect AAM
Childhood growth and menarche: Our analysis shows a sustained and
significant relationship between weight at 2 years, and weight at 4 years of
age, with growth in the first 24 months having the greatest effect
Conclusion:
Increased weight gain in infancy during the first 24 and 48 months is
associated with earlier AAM in girls. This has major implications for clinical
practice especially in developing countries. There is currently a poor
understanding of the underlying mechanisms underlying this phenomenon,
and more research in this area is required to understand the interplay
between environmental and genetic factors affecting the antenatal
environment, childhood growth, and menarche. === MT2017
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